.nav{
  height: rem(64px);
  border-bottom: rem(1px) solid #b2b2b2;
  position: fixed;
  width: 100%;
  top: 0;
  z-index: 99;
  background-color: #ffffff;
  .back-icon {
    width: rem(27px);
    height: rem(27px);
    position: absolute;
    top: rem(23px);
    left: rem(10px);
    background-image: url("./img/back.png");
    background-size: cover;
  }
  .title {
    font-size: rem(17px);
    color: #2f2f2f;
    text-align: center;
    line-height: rem(84px);
  }
}